Safety risk is reduced by steps applied in sequence and judged on practicability: avoid the hazard; else reduce its frequency to an acceptable level; else keep the frequency of the hazard becoming an accident as low as possible; else minimise the severity of loss. In design and operational rules: make the function safe (recognising the safe failure mode is relative), provide additional safety functions or barriers where needed and check their performance at sufficient intervals, and provide additional safety-related information and constraints on application, maintenance and operation.
The graph holds this control, the 0 it maps to, and the evidence behind each claim, over MCP and REST.